I was just using mine a few weeks ago in the California desert and made contacts all across the country. Depending on your soil conditions you can simply lay it on the ground but it comes with a bunch of stakes that holds the wires about 18" off the ground, which works a little better.
You can use half the antenna which looks like a 300ft long dipole on the ground and its supposed to launch signals at both a high angle for NVIS comms and it claims to also launch a vertically polarized wave off the ends. Using the complete antenna resembling a giant "H" is supposed to be a little more efficient and more directional off the ends.
I had an antenna similar to a G5RV set up around 25ft at the apex and the ends were about 6ft off the ground at the same location as the Eyring. The G5RV was a good S unit stronger on all bands 80m and up, both local and DX. Tuning around on 160m I found the Eyring works a whole lot better there than the G5RV simply because the G5RV is just too short to be effective on that band and the Eyring is a little larger than a full size half wave dipole on 160. I looked up the patents and the balun is simply a 4:1 and the H shaped version has a broad band power divider to feed the two sets of dipoles.
Bottom line is the Eyring antennas do work but there not very efficient. They are easy to setup requiring no masts, guy wires, etc. They are very stealthy and good if you need an HF antenna at an airport since you can land a helicopter right on top of it without crashing into masts and wires.
These came out in the mid 80's if my memory is working and the US military bought a bunch but they never really caught on. Israel also bought some and a guy there is selling them new surplus in the $100 range.
prcguy
I have in my parts bin a Mil. "H" ground antenna, got this right after Desert Storm 1 and was brand new. I have played with this with a CB a few years ago but could not get it far away enough from the truck (did not have enough coax) but still made some long distance contacts with folks running high power from 100 miles or so. I was not running power.
Any thoughts on this antenna for possible field day and possible emergency ops. use.
https://encrypted-tbn3.gstatic.com/...YKD-pRi53AXe3794P747_i79wzqHpwTUTViEGyUPdNPzw
The are called eyering antenna's.